Automatic fire alarm



Feb. 11, 1930. P. GERST AUTOMATIC FIRE ALARM Filed Feb. 9, 1928 [HZ/6726207: V

l-atented Feb. 11, 1936.) 1 ya a e 9 UNETED STATES PATENT QFICE PAUL GER-ST, OF ALTSTETTEN-ZURICH, SWITZERLAND AUTOMATIC FIRE ALARM Application filed February 9, 1928, Serial No. 253,133, and in Switzerland November 17, 1927.

This invention relates to an electric device or rollers a to which coil springs formed with for use principally as an automatic fire alarm, arms (Z are applied. The arms (Z are engaged and the invention consists in the provision of in the twin wires so as to apply tension to the an insulating block across which a pair of latter. If the insulation should burn through,

wires, forming part of an alarm circuit, is the wires will be caused by the tension to constretched and normally separated by distact with each other and close the alarm cirtanced studs connected to the block, one of cuit. Thus the alarm will be ooerated whethsaid studs being adapted to fuse readily so as er the wires be exposed direct to the flame to allow the wires, which are tensioned transor merely to the heat.

10 versely, to make contact with the other stud I claim: 60 for closing the alarm circuit if the tempera- 1. An automatic fire alarm comprising an ture in the room should rise excessively. insulating block, a pair of wires stretched Fig. l of the accompanying drawings is a across said block and tensioned transversely diagrammatic view of the device as applied so as to have a tendency to meet, and a pair of to a wall or the like, distanced studs on the block whereby said 65 Fig. 2, a sectional view of the insulating wires are normally separated, one of said block and its cover, and studs being adapted to fuse at excessive room Fig. 3, a view of a wire support used in contemperature so as to allow the wires to be elecjunction with the insulating block. trically connected through the other stud.

The alarm circuit includes a pair of wires 2. A structure as claimed in claim 1 where- '10 Z) and 0 which are stretched along a wall or a in the wire portions outside the block bear ceiling. One of the supports for the wires against each other and are relatively insuconsists of a block 6 of insulating material to lated with readily combustible material, and which two studs f and g are secured at a disincluding means for tensioning the wires tance apart. The stud f, which is prefe ably consisting of studs which hold the insulated 7 elongated in the direction of the stud g, as wire portions, and spring arms arranged on shown, is made of brass, whereas the smaller said latter studs and engaging the adjacent stud g is made of some material such as wood wire portions. metal or the like, adapted to fuse readily, say PAUL GERST. 39 at about C. The block is provided with a cover it which is formed with apertures m and 12 allowing the air to circulate freely across the stud g so as to fuse it if the temperature in the room should rise sufficiently. 35 The wires 5 and 0 are led through the box thus formed, the wire portions inside the box being bared and placed on the studs 7 and 9 so as to be normally kept apart by the latter. Tension is applied to the wires so that if the stud g should fuse, both wires will be applied 99 to the stud 7 and connected electrically through the latter for closing the alarm circuit.

The wire portions outside the box are in sulated with some readily combustible material. Preferably they are first covered with a layer of wood metal and then with cotton which in its turn is covered with artificial silk. These insulated wire portions, which are twisted together, are supported by studs 1v 

